UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

(Mark One)

For the fiscal year ended December 31, 2024

OR

Commission File Number 001-39045

IGM Biosciences, Inc.

(Exact name of Registrant as specified in its Charter)

Registrant’s telephone number, including area code: (650) 965-7873

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the Registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The aggregate market value of the voting and non-voting common stock held by non-affiliates of the Registrant, based on the closing price of a share of the Registrant’s common stock on June 28, 2024 as reported by the Nasdaq Global Select Market on such date was approximately $50.7 million. Shares of the Registrant’s common stock held by each executive officer, director and holder of 5% or more of the outstanding common stock have been excluded in that such persons may be deemed to be affiliates. This calculation does not reflect a determination that certain persons are affiliates of the Registrant for any other purpose.

As of February 28, 2025, the Registrant had 34,388,419 shares of common stock, $0.01 par value per share, and 25,386,983 shares of non-voting common stock, $0.01 par value per share, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Certain sections of the Registrant’s definitive Proxy Statement to be filed in connection with the Registrant’s 2025 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such definitive Proxy Statement will be filed with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days of the Registrant’s fiscal year ended December 31, 2024.

EXPLANATORY NOTE

IGM Biosciences, Inc. (the Company) is filing this Amendment No. 1 (this Amendment) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2024 (the Original 10-K) solely to provide additional information required by Part III of Form 10-K that was previously omitted from the Original 10-K, in reliance on General Instruction G(3) of Form 10-K because a definitive proxy statement containing such information will not be filed within 120 days after the end of December 31, 2024. The Part III information may be incorporated by reference from the Company’s definitive proxy statement, or such information may be included in an amendment to the Form 10-K. This Amendment does not change the previously reported financial statements or any other disclosure contained in Part I or Part II of the Original 10-K.

Table of Contents

PART III

Item 10. Directors, Executive Officers and Corporate Governance.

BOARD OF DIRECTORS AND CORPORATE GOVERNANCE

The following table sets forth the names, ages as of March 31, 2025 and certain other information for each member of our board of directors:

Class I Directors

Julie Hambleton, M.D. has served as a member of our board of directors since August 2018. Dr. Hambleton served as Interim President & CEO, Arch Oncology, a private company, from August 2020 to March 2021. From June 2018 until her retirement in April 2020, Dr. Hambleton served as Senior Vice President, Chief Medical Officer, Head of Development at IDEAYA Biosciences, an oncology medicine company. From September 2017 to May 2018 and from March 2016 to May 2016, Dr. Hambleton served as an independent strategic consultant for various life sciences companies. From May 2016 to September 2017, she served as Vice President, Head U.S. Medical at Bristol-Myers Squibb, a global biopharmaceutical company. From August 2015 to February 2016, Dr. Hambleton served as Executive Vice President, Chief Medical Officer at Five Prime Therapeutics, a biotechnology company, and as Senior Vice President, Chief Medical Officer from December 2012 to August 2015. From April 2010 to November 2012, Dr. Hambleton served as Vice President, Clinical Development at Clovis Oncology, and from 2003 to 2010, Dr. Hambleton held increasing roles of responsibility in BioOncology at Genentech. Dr. Hambleton has served on the board of directors of SpringWorks Therapeutics, a biopharmaceutical company, since May 2020 and Erasca, Inc., a biotechnology company, since March 2021. Dr. Hambleton completed her hematology-oncology training at the University of California, San Francisco, where she then served on the faculty from 1993 to 2003.

We believe Dr. Hambleton is qualified to serve on our board of directors because of her extensive career in the biotechnology industry, her executive and leadership experience and her medical expertise in hematology/oncology and internal medicine.

William Strohl, Ph.D. has served as a member of our board of directors since August 2018. In August 2016, Dr. Strohl founded BiStro Biotech Consulting, a biotechnology consulting company, of which he also serves as President. From February 2016 to August 2016, Dr. Strohl served as Vice President and Biologics Fellow at Janssen BioTherapeutics, the therapeutic biologics organization within the Janssen Research & Development division of Johnson & Johnson, a multinational medical devices and pharmaceutical company, and served as its Vice President and Head from October 2013 to February 2016. Prior to that, from April 2008 to October 2013, Dr. Strohl served as Head of Antibody Discovery at Janssen BioTherapeutics. Dr. Strohl has also held various roles at Merck, a pharmaceutical company, including leading Natural Products Biology and leading Biologics discovery efforts and was a Professor in the Department of Microbiology and the Program of Biochemistry at The Ohio State University. Dr. Strohl received a B.S. in Biology from Central Michigan University and a Ph.D. in Microbiology from Louisiana State University.

We believe Dr. Strohl is qualified to serve on our board of directors because of his extensive career in the biotechnology industry, his leadership experience and his educational background in biology, chemistry and microbiology.

Jakob Haldor Topsøe has served as a member of our board of directors since August 2018. Since June 2015, Mr. Topsøe has served as Chairman of the board of directors of Topsøe Holding A/S, and has served on the board of directors of Topsoe A/S, a Danish catalysis and chemical processing company and a subsidiary of Topsøe Holding A/S, since October 2010 and as its Vice Chairman since August 2016. Since January 2009, Mr. Topsøe has served as Partner at AMBROX Capital, a Danish investment management firm, and as Associate Partner since September 2016. From 1996 to 2008, Mr. Topsøe was employed in various functions within Alfred Berg/ABN Amro Bank including Head of Equities, Denmark. Mr. Topsøe served as a member of the board of directors of Motortramp, a Danish provider of marine transportation services, and Dampskibsselskabet Orients Fond, a Danish charitable foundation, from 2017 to October 2020. Mr. Topsøe received a Graduate Diploma in Business Administration (Finance) from the Copenhagen Business School.

We believe Mr. Topsøe is qualified to serve on our board of directors because of his investment experience, leadership experience and background and his affiliation with our lead investor.

Class II Directors

M. Kathleen Behrens, Ph.D. has served as a member of our board of directors since January 2019. Since December 2009, Dr. Behrens has served as an independent life sciences consultant and investor. From January 2012 to June 2014, she served as the Co-Founder, President, Chief Executive Officer and director of the KEW Group, a private oncology services company. From 1996 to December 2009, Dr. Behrens served in various roles at RS Investments, an investment management and research firm, including as a General Partner for selected venture funds. Prior to this, from 1983 to 1996, she served as a General Partner and Managing Director at Robertson Stephens & Co. Since March 2009, Dr. Behrens has served as a member of the board of directors of Sarepta Therapeutics, a medical research and drug development company, and as Chairwoman since April 2015, as well as chair of its audit committee and a member of its research and development committee. She has served as Chairwoman of the board of directors of MiMedx Group, a biomedical company, since June 2019, and as a member of its nominating and governance committee and audit committee. Dr. Behrens served on the board of directors of Amylin Pharmaceuticals, a biopharmaceutical company, from June 2009 until its sale to Bristol-Myers Squibb in 2012. She previously served as a member of the President’s Council of Advisors on Science and Technology (PCAST) from 2001 to early 2009 and as Chairwoman of its subcommittee on Personalized Medicine. She has also spent time as a public-market biotechnology securities analyst and a venture capitalist focusing on healthcare, technology and related investments. She also previously served on the Board on Science, Technology and Economic Policy for the National Research Council and as a Director, President and Chairwoman of the National Venture Capital Association. Dr. Behrens received a B.S. in Biological Sciences and a Ph.D. in Microbiology from the University of California, Davis.

We believe Dr. Behrens is qualified to serve on our board of directors because of her extensive experience in the life sciences field, her executive and board leadership experience and her medical expertise in biology and microbiology.

Elizabeth H.Z. Thompson, Ph.D. has served as a member of our board of directors since October 2023. Dr. Thompson has served Acadia Pharmaceuticals as Executive Vice President, Research and Development since April 2024. Dr. Thompson previously served Horizon Therapeutics Public Limited Company as Executive Vice President, Research and Development from March 2021 until Horizon was acquired by Amgen in October 2023, continuing as Executive Vice President, Research and Development, Rare Disease at Amgen from October 2023 until January 2024. She also served as Vice President, Development and External Search at Horizon from January 2020 to March 2021 and Vice President, Clinical Development, Rare Disease at Horizon from June 2018 to January 2020. Dr. Thompson received a B.S. in Chemistry from Harvey Mudd College and a Ph.D. in Macromolecular and Cellular Structure and Chemistry from The Scripps Research Institute.

We believe Dr. Thompson is qualified to serve on our board of directors because of her extensive experience in the life sciences industry, her executive leadership experience, and her educational background.

Christina Teng Topsøe has served as a member of our board of directors since August 2018, and previously served as an observer on our board of directors beginning in 2013. Since March 2013, Ms. Topsøe has served on the board of directors of Topsoe A/S, and has served on the board of directors of Topsøe Holding A/S, its holding company, since June 2015. Ms. Topsøe previously was a lawyer at Allen & Overy LLP and Simpson Thacher and Bartlett LLP. Ms. Topsøe pursued a B.A. in Chinese Studies from the University of Copenhagen, studied Chinese Language and Literature at Peking University, and received an LL.B. from the University of London and an M.B.A. from London Business School and Columbia Business School.

We believe Ms. Topsøe is qualified to serve on our board of directors because of her leadership experience and perspective as an entrepreneur and her affiliation with our lead investor.

Class III Directors

Felix J. Baker, Ph.D. has served as a member of our board of directors since January 2021. Dr. Baker is a Managing Member of Baker Bros. Advisors LP (BBA), a biotechnology-focused investment adviser to fund partnerships whose investors are primarily endowments and foundations. Dr. Baker founded BBA, together with his brother Julian Baker, in 2000. Dr. Baker has served on the boards of biotechnology and pharmaceutical companies, including Seagen from July 2003 to December 2023, Kodiak Sciences since September 2015, Kiniksa Pharmaceuticals since October 2015, Kymera Therapeutics since March 2024, and Bicycle Therapeutics since April 2024, and he previously served on the board of Talis Biomedical from July 2013 to March 2023 and Alexion Pharmaceuticals from June 2015 to February 2021. Dr. Baker holds a B.S and a Ph.D. in Immunology from Stanford University, where he also completed two years of medical school.

We believe Dr. Baker is qualified to serve on our board of directors because of his background, knowledge of our industry, extensive investment and leadership experience and his affiliation with one of our investors.

Mary Beth Harler, M.D. has served as our Chief Executive Officer and has been a member of our board of directors since October 2024. Dr. Harler also served as our Head of Research and Autoimmunity from January 2024 until October 2024 and as President of Autoimmunity and Inflammation from October 2021 until May 2024. Prior to joining IGM. Dr. Harler was Senior Vice President, Head of Immunology and Fibrosis Development from November 2019 to October 2021, Head of Innovative Medicines Development from December 2017 to November 2019, Head of Innovative Medicines Development and Head of Innovative Clinical Development in the cardiovascular, fibrosis, immunoscience and genetically-defined diseases group from October 2016 to November 2019 at Bristol Myers Squibb. Dr. Harler received a B.S. from Wheeling University in West Virginia and an M.D. from Marshall University. She completed training as a general surgeon at Brown University’s Rhode Island Hospital, where she was also a research fellow with a focus on the role of immune cells in wound healing.

We believe Dr. Harler is qualified to serve on our board of directors because of her expertise and experience as our Chief Executive Officer, her depth and expertise in the life sciences industry, her leadership experience and her educational background.

Michael Lee has served as a member of our board of directors since July 2019. Mr. Lee has served as Co-Founder and Portfolio Manager at Redmile Group, an investment advisory firm since 2007. Prior to Redmile, Mr. Lee worked as a biotechnology investor at Steeple Capital, an investment management firm, and as an analyst at Welch Capital Partners, an investment advisory firm, and Prudential Equity Group, a financial services company. Mr. Lee has served on the board of directors of Fate Therapeutics, Inc., a biopharmaceutical company, since July 2018 and Shattuck Labs, Inc., a biotechnology company, since June 2020. Mr. Lee holds a B.S. in Molecular and Cellular Biology from the University of Arizona.

We believe Mr. Lee is qualified to serve on our board of directors because of his background, knowledge of our industry and extensive investment and leadership experience.

Family Relationships

Christina Teng Topsøe and Jakob Haldor Topsøe, each a member of our board of directors, are first cousins. There are no other family relationships among any of our directors or executive officers.

Director Independence

Our common stock is listed on the Nasdaq Global Select Market. Under the listing standards of Nasdaq, independent directors must comprise a majority of our board of directors. In addition, the listing standards of Nasdaq require that, subject to specified exceptions, each member of our audit, compensation and corporate governance and nominating committees be independent. Audit committee members and compensation committee members must also satisfy the independence criteria set forth in Rule 10A-3 and Rule 10C-1, respectively, under the Exchange Act. Under the listing standards of Nasdaq, a director will only qualify as an “independent director” if, in the opinion of that company’s board of directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director.

To be considered to be independent for purposes of Rule 10A-3 and under the listing standards of Nasdaq, a member of an audit committee of a listed company may not, other than in his or her capacity as a member of the audit committee, the board of directors or any other board committee: (1) accept, directly or indirectly, any consulting, advisory or other compensatory fee from the listed company or any of its subsidiaries or (2) be an affiliated person of the listed company or any of its subsidiaries.

To be considered independent for purposes of Rule 10C-1 and under the listing standards of Nasdaq, the board of directors must affirmatively determine that each member of the compensation committee is independent, including a consideration of all factors specifically relevant to determining whether the director has a relationship to the company which is material to that director’s ability to be independent from management in connection with the duties of a compensation committee member, including: (1) the source of compensation of such director, including any consulting, advisory or other compensatory fee paid by the company to such director and (2) whether such director is affiliated with the company, a subsidiary of the company or an affiliate of a subsidiary of the company.

Our board of directors has undertaken a review of its composition, the composition of its committees and the independence of each director and considered whether any director has a material relationship with us that could compromise his or her ability to exercise independent judgment in carrying out his or her responsibilities. Based upon information requested from and provided by each director concerning his background, employment and affiliations, including family relationships, our board of directors has determined that Drs. Baker, Behrens, Hambleton, and Thompson, Messrs. Lee and Topsøe, and Ms. Topsøe, representing seven of our nine directors, do not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director and that each of these directors is “independent” as that term is defined under the listing standards of Nasdaq. In addition, our board of directors has determined that all members of our audit, compensation, and corporate governance and nominating committees satisfy the independence standards for committee members established by applicable SEC rules and regulations and the listing standards of Nasdaq.

In making these determinations, our board of directors considered the current and prior relationships that each non-employee director has with our company and all other facts and circumstances our board of directors deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director, and the transactions involving them described in the section titled “Certain Relationships, Related Party and Other Transactions.”

Board Leadership Structure

Although we do not require separation of the positions of Chair of our board of directors and Chief Executive Officer, we have in the past chosen to have different individuals serving in such roles. The position of Chair of our board of directors has not yet been filled following the retirement of Dr. Michael Loberg from our board of directors in October 2023. We continue to evaluate our options for filling the Chair role based on the board’s assessment of stockholders’ long-term interests under the prevailing circumstances.

Committees of our Board of Directors

Our board of directors has established an audit committee, a compensation committee, a corporate governance and nominating committee and a research and clinical development committee. The composition and responsibilities of each of the committees of our board of directors are described below. Members serve on these committees until their resignation or until otherwise determined by our board of directors. Our board of directors may establish other committees as it deems necessary or appropriate from time to time.

Audit Committee

Our audit committee consists of Drs. Behrens, Hambleton and Thompson, with Dr. Behrens serving as chair. Our board of directors has determined that each of the members of our audit committee satisfies the independence requirements under the listing standards of Nasdaq and Rule 10A-3 of the Exchange Act. Our board of directors has determined that Dr. Behrens is an “audit committee financial expert” within the meaning of SEC rules and regulations. Each member of our audit committee can read and understand fundamental financial statements in accordance with applicable requirements. In arriving at these determinations, our board of directors examined each audit committee member’s scope of experience and the nature of their employment in the corporate finance sector.

Our audit committee oversees our corporate accounting and financial reporting process and assists our board of directors in monitoring our financial systems. Our audit committee is also responsible for, among other things:

Our audit committee operates under a written charter that satisfies the applicable rules and regulations of the SEC and the listing standards of Nasdaq. A copy of the charter for our audit committee is available on our investor relations website at https://investor.igmbio.com/. During 2024, our audit committee held four meetings.

Compensation Committee

Our compensation committee consists of Drs. Behrens and Thompson and Ms. Topsøe, with Ms. Topsøe serving as chair. Our board of directors has determined that each of the members of our compensation committee is independent under the listing standards of Nasdaq and a “non-employee director” as defined in Rule 16b-3 under the Exchange Act.

Our compensation committee oversees our compensation policies, plans, and benefits programs. The compensation committee is also responsible for, among other things:

Our compensation committee operates under a written charter that satisfies the applicable rules and regulations of the SEC and the listing standards of Nasdaq. A copy of the charter for our compensation committee is available on our investor relations website at https://investor.igmbio.com/. During 2024, our compensation committee held eight meetings.

Corporate Governance and Nominating Committee

Our corporate governance and nominating committee consists of Drs. Behrens and Thompson and Ms. Topsøe, with Ms. Topsøe serving as chair. Our board of directors has determined that each member of our corporate governance and nominating committee is independent under the listing standards of Nasdaq.

Our corporate governance and nominating committee oversees and assists our board of directors in reviewing and recommending nominees for election as directors. The corporate governance and nominating committee is also responsible for, among other things:

Our corporate governance and nominating committee operates under a written charter that satisfies the listing standards of Nasdaq. A copy of the charter for our corporate governance and nominating committee is available on our investor relations website at https://investor.igmbio.com/. During 2024, our corporate governance and nominating committee held four meetings.

Research and Clinical Development Committee

Our research and clinical development committee consists of Drs. Baker, Hambleton, Strohl and Thompson, with Drs. Hambleton and Strohl serving as co-chairs.

Specific responsibilities of our research and clinical development committee include:

Our research and clinical development committee operates under a written charter, and during 2024, the committee held three meetings.

Attendance at Board and Stockholder Meetings

During our fiscal year ended December 31, 2024, our board of directors held six meetings (including regularly scheduled and special meetings), and each director attended at least 75% of the aggregate of (i) the total number of meetings of our board of directors held during the period for which he or she has been a director and (ii) the total number of meetings held by all committees of our board of directors on which he or she served during the periods that he or she served on such committee, other than Dr. Loberg.

Although we do not have a formal policy regarding attendance by members of our board of directors at annual meetings of stockholders, we strongly encourage, but do not require, our directors to attend. All of our directors then in office virtually attended the 2024 Annual Meeting of Stockholders.

Compensation Committee Interlocks and Insider Participation

During 2024, Drs. Behrens and Thompson and Ms. Topsøe served on our compensation committee. None of the members of our compensation committee is currently, or has been at any time, one of our officers or employees. None of our executive officers currently serves, or has served during the past fiscal year, as a member of the board of directors or the compensation committee (or other board committee performing equivalent functions or, in the absence of any such committee, the entire board of directors) of any entity that has one or more of its executive officers serving as a member of our board of directors or our compensation committee. Ms. Topsøe may be deemed to have an interest in certain transactions requiring disclosure under Item 404 of Regulation S-K under the Securities Act of 1933, as amended (the Securities Act). These transactions are disclosed in the section titled “Certain Relationships, Related Party and Other Transactions,” and such disclosure is incorporated by reference herein.

Corporate Governance Guidelines and Code of Business Conduct and Ethics

Our board of directors has adopted Corporate Governance Guidelines that address items such as the qualifications and responsibilities of our directors and director candidates and corporate governance policies and standards applicable to us in general. In addition, our board of directors has adopted a Code of Business Conduct and Ethics that applies to all of our employees, officers and directors, including our Chief Executive Officer, Chief Financial Officer and other executive and senior financial officers. The full text of our Corporate Governance Guidelines and our Code of Business Conduct and Ethics is posted on our investor relations website at https://investor.igmbio.com/. We will post any amendments to our Code of Business Conduct and Ethics and any waivers of our Code of Business Conduct and Ethics for directors and executive officers on the same website or in filings under the Exchange Act.

Role of the Board in Risk Oversight

Our board of directors has an active role, as a whole and also at the committee level, in overseeing the management of our risks. Our board of directors is responsible for general oversight of risks and regular review of information regarding our risks, including credit risks, liquidity risks and operational risks. Our compensation committee is responsible for overseeing the management of risks relating to our executive compensation plans and arrangements. Our audit committee is responsible for overseeing the management of risks relating to accounting matters and financial reporting. Our corporate governance and nominating committee is responsible for overseeing the management of risks associated with the independence of our board of directors and potential conflicts of interest. Although each committee is responsible for evaluating certain risks and overseeing the management of such risks, our entire board of directors is regularly informed through discussions from committee members about such risks. Our board of directors believes its administration of its risk oversight function has not negatively affected the board of directors’ leadership structure.

Insider Trading Policy and Hedging Prohibition

We have adopted an Insider Trading Policy that governs the purchase, sale and/or other dispositions of our securities by our directors, officers and employees, and that is reasonably designed to promote compliance with insider trading laws, rules and regulations.

As part of our Insider Trading Policy, our employees (including our executive officers and the non-employee members of our board of directors) are prohibited from trading in publicly-traded options, such as puts and calls, and other derivative securities with respect to our securities. This includes any hedging or similar transaction designed to decrease the risks associated with holding shares of our common stock. A copy of our insider trading policy was filed as an Exhibit to our Original Form 10-K. We comply with insider trading laws, rules and regulations and any applicable listing standards in any transactions involving our own securities.

EXECUTIVE OFFICERS

The following table sets forth certain information about our executive officers as of March 31, 2025. Officers are elected by our board of directors to hold office until their successors are elected and qualified.

For the biography of Dr. Harler, please see “Board of Directors and Corporate Governance—Continuing Directors.”

Lisa L. Decker, Ph.D. has served as our Chief Business Officer since March 2021. Prior to joining us, Dr. Decker served as Chief Business Officer of Atreca, a biopharmaceutical company, from June 2019 until March 2021. Dr. Decker also previously served in various roles at Nektar Therapeutics, a development stage biopharmaceutical company, from August 2008 to June 2019, including as Vice President of Business Development from August 2017 until June 2019, Executive Director, Business Development from August 2012 until August 2017, Executive Director, Business Strategy and Operations from January 2010 until July 2012, and Senior Director, Alliance Management from August 2008 until December 2009. Prior to this, Dr. Decker served in a number or roles at the Office of Technology Management at the University of Massachusetts Medical School from 2000 until 2008. Dr. Decker previously served on the board of directors of Chimerix, Inc. from December 2023 until April 2025.Dr. Decker holds a Ph.D. in Immunology from Tufts University School of Medicine and conducted her postdoctoral training at Harvard Medical School.

Misbah Tahir joined IGM in January 2019 as Chief Financial Officer. He previously served at Dermira in various roles from 2014 to 2018, most recently as Vice President, Finance. Prior to joining Dermira in 2014, he held finance leadership positions at Onyx Pharmaceuticals, Human Genome Sciences and Amgen. Mr. Tahir began his career as a management consultant at the consulting firm of Oliver Wyman. He received a B.A. in International Relations from the University of Pennsylvania and an M.B.A. from the University of Michigan Business School. Mr. Tahir is a certified public accountant, inactive, in the state of California.

Item 11. Executive Compensation.

Processes and Procedures for Compensation Decisions

Our compensation committee is responsible for the executive compensation programs for our executive officers and reports to our board of directors on its discussions, decisions and other actions. Typically, our Chief Executive Officer makes recommendations to our compensation committee, often attends committee meetings and is involved in the determination of compensation for the respective executive officers who report to her, except that the Chief Executive Officer does not make recommendations as to her own compensation. Our Chief Executive Officer makes recommendations to our compensation committee regarding short- and long-term compensation for all executive officers (other than herself) based on our results, an individual executive officer’s contribution toward these results and performance toward individual goal achievement. Our compensation committee then reviews the recommendations and other data. Our compensation committee makes decisions as to total compensation for each executive office, although it may instead, in its discretion, make recommendations to our board of directors regarding executive compensation for its approval.

Our compensation committee is authorized to retain the services of one or more executive compensation advisors, as it sees fit, in connection with the establishment of our compensation programs and related policies. In 2024, our compensation committee retained Aon, a national compensation consultant, to provide it with information, recommendations and other advice relating to executive compensation on an ongoing basis. Aon serves at the discretion of our compensation committee. As part of its engagement, Aon assists our compensation committee in developing an appropriate group of peer companies to help us determine the appropriate level of overall compensation for our executive officers, as well as assess each separate element of compensation, with a goal of ensuring that the compensation we offer to our executive officers is competitive and fair.

Our compensation committee periodically considers and assesses Aon’s independence, including whether Aon has any potential conflicts of interest with our company or members of our compensation committee. In connection with Aon’s engagement, our compensation committee conducted such a review and concluded that it was not aware of any conflict of interest that had been raised by work performed by Aon or the individual consultants employed by Aon that perform services for our compensation committee.

Our named executive officers for the fiscal year ended December 31, 2024, which consist of all individuals who served as our principal executive officer during the year ended December 31, 2024, the next two most highly compensated executive officers who were serving as executive officers as of December 31, 2024, and two individuals who would have been one of our two most highly compensated executive officers had they been serving as an executive officer as of December 31, 2024, are:

Summary Compensation Table

The following table provides information regarding the compensation of our named executive officers during the years ended December 31, 2024 and 2023.

The lesser number of RSUs received by each participant in the Option Exchange Program was determined in accordance with exchange ratios designed to be approximately value-neutral from a financial accounting perspective. Accordingly, the fair value of the options held by each of our named executive officers that were cancelled in the Option Exchange Program was equivalent to the fair value of the RSUs granted to our named executive officers in the Option Exchange Program, as computed in accordance with Topic 718. No incremental values are reported in the Summary Compensation Table with respect to the Option Exchange Program.

Outstanding Equity Awards at 2024 Year-End

The following table provides information regarding outstanding equity awards held by our named executive officers as of December 31, 2024.

Grant of Certain Equity Awards Close in Time to the Release of Material Nonpublic Information

Employment Arrangements

Mary Beth Harler, M.D.

In October 2024, we entered into an employment agreement with Mary Beth Harler, our Chief Executive Officer. The employment agreement has no specific term and provides that Dr. Harler is an at-will employee. The employment agreement supersedes all existing agreements and understandings that Dr. Harler may have concerning her employment relationship with us. The employment letter also provides Dr. Harler with severance and change in control benefits pursuant to our Change in Control and Severance Policy

described below. Dr. Harler’s annual base salary was $640,000 for 2024 and was subsequently increased to $667,345, effective January 1, 2025. She is currently eligible for an annual target cash incentive payment equal to 55% of her annual base salary.

Misbah Tahir

In August 2019, we entered into a confirmatory employment letter with Misbah Tahir, our Chief Financial Officer. The employment letter has no specific term and provides that Mr. Tahir is an at-will employee. The employment letter supersedes all existing agreements and understandings that Mr. Tahir may have concerning his employment relationship with us. The employment letter also provides Mr. Tahir with severance and change in control benefits pursuant to our Change in Control and Severance Policy described below. Mr. Tahir’s annual base salary was $498,726 for 2024 and was subsequently increased to $523,662, effective January 1, 2025. He is currently eligible for an annual target cash incentive payment equal to 45% of his annual base salary.

Lisa L. Decker, Ph.D.

In February 2021, we entered into an employment agreement with Lisa Decker, our Chief Business Officer. The employment agreement has no specific term and provides that Dr. Decker is an at-will employee. The employment agreement also provides Dr. Decker with severance and change in control benefits pursuant to our Change in Control and Severance Policy described below. Dr. Decker’s annual base salary was $463,146 for 2024 and was subsequently increased to $486,303, effective January 1, 2025. She is currently eligible for an annual target cash incentive payment equal to 40% of her annual base salary.

Fred Schwarzer

In August 2019, we entered into a confirmatory employment letter with Fred Schwarzer, our former Chief Executive Officer and President. The employment letter had no specific term and provided for Mr. Schwarzer’s at-will employment. The employment letter also provided Mr. Schwarzer with severance and change in control benefits pursuant to our Change in Control and Severance Policy described below. Mr. Schwarzer’s annual base salary was $672,669 for 2024.

In September 2024, we entered into a transition and consulting agreement with Mr. Schwarzer, in connection with his resignation as Chief Executive Officer, President and a member of our board of directors (the Schwarzer Consulting Agreement). Mr. Schwarzer will be paid $28,030 for each one-month period in which he is available to provide consulting services, and $5,500 per month for 18 months to facilitate health care continuation coverage. Each of Mr. Schwarzer’s outstanding equity awards that would have been eligible to vest based on service during the period in which the Schwarzer Consulting Agreement is in effect will continue to vest during such period pursuant to the terms and conditions of the 2018 Plan. The Schwarzer Consulting Agreement provides for certain benefits payable to Mr. Schwarzer upon certain qualifying terminations of service, as described below.

Bruce Keyt, Ph.D.

In August 2019, we entered into a confirmatory employment letter with Bruce Keyt, our Chief Scientific Officer. The employment letter has no specific term and provides that Dr. Keyt is an at-will employee. The employment letter supersedes all existing agreements and understandings that Dr. Keyt may have concerning his employment relationship with us. The employment letter also provides Dr. Keyt with severance and change in control benefits pursuant to our Change in Control and Severance Policy described below. Dr. Keyt’s annual base salary was $511,813 for 2024.

In October 2024, we entered into a transition and consulting agreement with Dr. Keyt, in connection with his resignation as Chief Scientific Officer (the Keyt Consulting Agreement). Dr. Keyt will be paid $21,326 for each one-month period in which he is available to provide consulting services, and $5,500 per month for 18 months to facilitate health care continuation coverage, provided that all such payments would cease if his service was terminated for cause. Each of Dr. Keyt’s outstanding equity awards that would have been eligible to vest based on service during the period in which the Keyt Consulting Agreement is in effect will continue to vest during such period pursuant to the terms and conditions of the 2018 Plan. The Keyt Consulting Agreement provides for certain benefits payable to Dr. Keyt upon certain qualifying terminations of service, as described below.

Chris H. Takimoto, M.D., Ph.D., F.A.C.P.

In July 2021, we entered into an employment agreement with Chris Takimoto, our former Chief Medical Officer. The employment agreement had no specific term and provided for Dr. Takimoto’s an at-will employment. The employment agreement also provided Dr. Takimoto with severance and change in control benefits pursuant to our Change in Control and Severance Policy described below. Dr. Takimoto’s annual base salary was $505,903 for 2024. Dr. Takimoto resigned as our Chief Medical Officer, effective October 1, 2024.

Potential Payments upon Termination or Change in Control

Severance Policy

In order to recruit and maintain a stable and effective management team, our compensation committee believes it is appropriate and necessary to provide assurance of certain severance and change in control benefits approved by the compensation committee, in consultation with Aon. We previously entered into participation agreements under our Change in Control and Severance Policy (the Severance Policy) with each of our named executive officers that provide for the severance and change in control benefits described below. Upon the termination of Mr. Schwarzer’s employment in September 2024 and the termination of each of Dr. Keyt’s and Dr. Takimoto’s employment in October 2024, each ceased to be eligible to participate in the Severance Policy.

Our board of directors has approved the following change in control and severance benefits for our current executive officers and other key employees (collectively, participants) pursuant to the Severance Policy. Unless sooner terminated by our board of directors or compensation committee or by the consent of an impacted participant, the Severance Policy had an initial term of three years, subject to potential extension upon the occurrence of certain events set forth in the Severance Policy. The Severance Policy was amended in April 2023 to provide that, following the conclusion of its initial term, the Severance Policy would automatically extend for an additional one year term on each successive anniversary of its effective date, provided that our board of directors or compensation committee may provide that the Severance Policy will not renew and will terminate upon the conclusion of the applicable one year term by providing notice to all affected participants at least 60 days prior to the applicable renewal date.

The Severance Policy provides that if we terminate a participant’s employment outside of the period beginning three months prior to and ending 12 months after a “change in control” (as defined in the Severance Policy) (such period, the change in control period) other than for “cause” (as generally defined in the Severance Policy), death or disability (or, in the case of Dr. Harler, if Dr. Harler terminates her employment due to a “constructive termination” (as defined in the Severance Policy)), the participant will receive the following:

The Severance Policy provides that if a participant’s employment is terminated during the change in control period either by us other than for cause, death or disability or by the participant due to a “constructive termination”, the participant will receive the following:

The Severance Policy also provides that if in connection with a change in control, a participant’s then-unvested time-based equity awards are not assumed or replaced or substituted with an equivalent award by the acquiror or successor corporation, then 100% of such equity awards will immediately vest and become exercisable (if applicable).

The Severance Policy provides that if we discover after a participant’s receipt of payments or benefits under the Severance Policy that grounds for the termination of the participant’s employment for cause existed, then the participant will not receive any further payments or benefits under the Severance Policy and, to the extent permitted under applicable laws, will be required to repay to us any payments or benefits he or she received under the Severance Policy (or any financial gain derived from such payments or benefits).

In addition, the Severance Policy provides that if any payments or benefits received by a participant under the Severance Policy or otherwise would constitute “parachute payments” within the meaning of Section 280G of the Internal Revenue Code of 1986 (the Code) and be subject to excise taxes imposed by Section 4999 of the Code, such amount will either be delivered in full or reduced so as not to be subject to excise taxation, whichever amount results in the higher after-tax payment to the participant. The Severance Policy does not require us to provide any tax gross-ups.

To receive the severance described above, the participant must sign and not revoke our standard separation agreement and release of claims within the timeframe that is set forth in the Severance Policy. Except for provisions providing for accelerated vesting of a participant’s performance-based equity awards upon a termination either by us other than for cause, death or disability or by the participant due to a constructive termination, the Severance Policy supersedes any provisions in a participant’s offer letter or equity award agreement that provide for accelerated vesting upon certain terminations of employment.

Schwarzer Consulting Agreement

Pursuant to the Schwarzer Consulting Agreement, if Mr. Schwarzer’s service is terminated by us other than for Cause (as defined in the Schwarzer Consulting Agreement), subject to his execution of a release of claims in favor of us, Mr. Schwarzer will become eligible to receive (i) cash compensation which otherwise would be payable to Mr. Schwarzer under the Schwarzer Consulting Agreement through the second anniversary of its effectiveness (the Schwarzer Expected Term), and (ii) accelerated vesting of his outstanding awards of RSUs and options (which options will remain exercisable through the date that is 3 months following the end of the Schwarzer Expected Term, subject to the terms of the 2018 Plan and the applicable option agreement).

If Mr. Schwarzer is unable to provide services under the Schwarzer Consulting Agreement due to his death or disability, he (or his estate) will similarly become eligible to receive (i) a lump sum payment equal to the cash compensation which otherwise would be payable to Mr. Schwarzer under the Schwarzer Consulting Agreement through the Schwarzer Expected Term, and (ii) accelerated vesting of his outstanding awards of RSUs and options.

If Mr. Schwarzer voluntary terminates service under the Schwarzer Consulting Agreement, he will continue to receive cash compensation which otherwise would be payable to him under the Schwarzer Consulting Agreement through the Schwarzer Expected Term, but all future equity vesting will cease and his outstanding stock options will remain exercisable only through the date that is 3 months following such termination of service.

Keyt Consulting Agreement

Pursuant to the Keyt Consulting Agreement, if Dr. Keyt’s service is terminated by us other than for Cause (as defined in the Keyt Consulting Agreement), subject to his execution of a release of claims in favor of us, Dr. Keyt will become eligible to receive (i) cash compensation which otherwise would be payable to Dr. Keyt under the Keyt Consulting Agreement through the second anniversary of its effectiveness (the Keyt Expected Term), and (ii) accelerated vesting of his outstanding awards of RSUs and options (which options will remain exercisable through the date that is 3 months following the end of the Keyt Expected Term, subject to the terms of the 2018 Plan and the applicable option agreement).

If Dr. Keyt is unable to provide services under the Keyt Consulting Agreement due to his death or disability, he (or his estate) will similarly become eligible to receive (i) a lump sum payment equal to the cash compensation which otherwise would be payable to Dr. Keyt under the Keyt Consulting Agreement through the Keyt Expected Term, and (ii) accelerated vesting of his outstanding awards of RSUs and options.

If Dr. Keyt voluntary terminates service under the Keyt Consulting Agreement, he will continue to receive cash compensation which otherwise would be payable to him under the Keyt Consulting Agreement through the Keyt Expected Term, but all future equity vesting will cease and his outstanding stock options will remain exercisable only through the date that is 3 months following such termination of service.

Executive Incentive Compensation Plan

In August 2019, our board of directors adopted an Executive Incentive Compensation Plan (the Bonus Plan). The Bonus Plan is administered by a committee appointed by our board of directors. Unless and until our board of directors determines otherwise, our compensation committee is the administrator of the Bonus Plan. The Bonus Plan allows our compensation committee to provide cash incentive awards to selected employees, including our named executive officers, determined by our compensation committee, based upon performance goals established by our compensation committee. Our compensation committee, in its sole discretion, establishes a target award for each participant under the Bonus Plan, which may be expressed as a percentage of the participant’s average annual base salary for the applicable performance period, a fixed dollar amount, or such other amount or based on such other formula as our compensation committee determines to be appropriate.

Under the Bonus Plan, our compensation committee determines the performance goals applicable to awards, which goals may include, without limitation: (i) research and development, (ii) regulatory milestones or regulatory-related goals, (iii) gross margin, (iv) financial milestones, (v) new product or business development, (vi) operating margin, (vii) product release timelines or other product release

milestones, (viii) publications, (ix) cash flow, (x) cash position, (xi) procurement, (xii) savings, (xiii) internal structure, (xiv) leadership development, (xv) project, function or portfolio-specific milestones, (xvi) partnering, license or research collaboration agreements, (xvii) capital raising, (xviii) initial public offering preparations, (xix) patentability, (xx) revenue, (xxi) revenue growth, (xxii) stock price, and (xxiii) individual objectives such as peer reviews or other subjective or objective criteria. As determined by our compensation committee, the performance goals may be based on GAAP or non-GAAP results and any actual results may be adjusted by our compensation committee for one-time items or unbudgeted or unexpected items and/or payments of actual awards under the Bonus Plan when determining whether the performance goals have been met. The goals may be on the basis of any factors our compensation committee determines relevant, and may be on an individual, divisional, business unit, segment or company-wide basis. Any criteria used may be measured on such basis as our compensation committee determines. The performance goals may differ from participant to participant and from award to award. Our compensation committee also may determine that a target award or a portion thereof will not have a performance goal associated with it but instead will be granted (if at all) in the compensation committee’s sole discretion.

All of the Company’s named executive officers participated in its annual cash incentive compensation program for 2024 (2024 Bonus Plan), which provided them with an opportunity to receive formula-based incentive amounts. These named executive officers’ target bonus opportunities under the 2024 Bonus Plan are expressed as a percentage of each named executive officer’s annual base salary. For 2024, the target bonus opportunity was 55% for Dr. Harler, 45% for Mr. Tahir, 40% for Dr. Decker, 55% Mr. Schwarzer, 45% for Dr. Keyt and 45% for Dr. Takimoto. Due to their terminations of employment in 2024, Mr. Schwarzer, Dr. Keyt and Dr. Takimoto were ineligible to receive a bonus under the 2024 Bonus Plan.

For 2024, the performance metrics for which achievement was measured to determine bonuses included corporate performance goals (including advancement of our research and development programs) and individual performance goals(other than in the case of Dr. Harler, whose bonus was measured solely against corporate performance goals).

The amounts in the Summary Compensation Table under the column “Non-equity incentive plan compensation” are based on the named executive officer’s target bonus amount multiplied by the achievement percentage set by our compensation committee, consistent with the determinations under the applicable year’s bonus plan.

For 2024, Fred Schwarzer elected to receive his bonus under the 2023 Bonus Plan in the form of RSU Awards, as described above in the footnotes to the Summary Compensation Table.

401(k) Plan

We maintain a tax-qualified 401(k) retirement plan for all U.S. employees, including our named executive officers, who satisfy certain eligibility requirements, including requirements relating to age and length of service. Under our 401(k) plan, employees may elect to defer up to all eligible compensation, subject to applicable annual Code limits. In 2023, we started a matching program, whereby we match employee contributions at a rate of $1.00 for each dollar contribution, up to 3% of an eligible employee’s gross salary, and at the rate of $0.50 for each dollar contribution up to an additional 2% of an eligible employee’s gross salary; employees must contribute at least 5% of their gross salary to receive the full company matching contribution. We intend for our 401(k) plan to qualify under Section 401(a) and 501(a) of the Code so that contributions by employees to our 401(k) plan, and income earned on those contributions, are not taxable to employees until withdrawn from our 401(k) plan. The 401(k) plan also permits contributions to be made on a post-tax basis for those employees participating in the Roth 401(k) plan component.

Director Compensation

In connection with our initial public offering, our board of directors adopted, and our stockholders approved, a compensation policy for our non-employee directors. This policy was developed with input from our compensation committee’s independent compensation consultant, Aon, regarding practices and compensation levels at comparable companies. It is designed to attract, retain and reward non-employee directors. Our compensation committee, with input from Aon, has made adjustments to our non-employee director compensation program, most recently in February 2024 in an effort to provide competitive compensation opportunities for our non-employee directors.

Under the outside director compensation policy, each non-employee director receives cash and equity compensation for his or her services as a member of our board of directors, as described below. We also reimburse our non-employee directors for reasonable, customary and documented travel expenses to meetings of our board of directors or its committees.

The director compensation policy includes a maximum annual limit of $750,000 or, in the first year of a non-employee director’s service on our board of directors, $1,000,000, of cash compensation and equity awards that may be paid, issued or granted to a

non-employee director in any fiscal year. For purposes of these limitations, the value of an equity award is based on its grant date fair value (determined in accordance with generally accepted accounting principles, or GAAP). Any cash compensation paid or equity awards granted to a person for his or her services as an employee, or for his or her services as a consultant (other than as a non-employee director), will not count for purposes of the limitation. The maximum limit does not reflect the intended size of any potential compensation or equity awards to our non-employee directors.

Cash Compensation

Under our outside director compensation policy, each non-employee director is paid an annual cash retainer of $40,000 and cash compensation based on role. In 2024, each non-employee director was entitled to receive the following cash compensation for his or her services under the policy:

In addition, each non-employee director who serves on the board of directors of one of our majority owned subsidiaries will be eligible to earn an additional $40,000 in annual fees for each subsidiary board on which he or she serves (paid quarterly in arrears on a prorated basis, provided that the fees for the first quarter during which the non-employee serves on a subsidiary board will not be prorated).

Each non-employee director who serves as a committee chair receives only the additional annual cash fee as the chair of the committee, and not the additional annual fee as a member of the committee. All cash payments to non-employee directors are paid quarterly in arrears on a prorated basis.

Each non-employee director may elect on an annual basis to convert 0%, 50% or 100% of his or her retainer cash compensation with respect to services to be performed in a future calendar quarter and otherwise scheduled to be paid following the completion of those services into a number of restricted stock units (RSUs and, such award, a Retainer Award) having a grant value equal to the aggregate amount of the elected percentage of the retainer cash compensation payable to such non-employee director under the policy for the applicable quarter (as determined on the applicable date of grant of such Retainer Award). The Retainer Awards are automatic and nondiscretionary and are granted on the last business day of each quarter with respect to the retainer cash compensation that would have been paid in such fiscal quarter. All RSUs underlying such Retainer Awards will be fully vested upon grant. The grant value for any Retainer Award is calculated based on the volume weighted average price of one share of our common stock over the fourth quarter of the year immediately preceding the year of the date of grant. Following the amendment of our outside director compensation policy in February 2024, our non-employee directors may make an irrevocable election to defer the delivery of the shares subject to any RSUs granted in respect of a Retainer Award, subject to the terms of our outside director compensation policy and a deferral election form.

Equity Compensation

Initial Options. Each person who first becomes a non-employee director after the effective date of the director compensation policy will be granted an initial award of a nonstatutory stock option (the Initial Option) to purchase shares of our common stock. Before the amendment of the policy in February 2024, each Initial Option covered a fixed number of 31,000 shares. From and after February 2024, each Initial Option will cover a fixed number of 58,800 shares of our common stock. The Initial Option will be scheduled to vest as to 1/3rd of the shares subject to the option on the first anniversary of the director’s commencement of service to us and 1/36th of the shares will vest each month thereafter, subject to continued service to us through each applicable vesting date. If the person was a member of our board of directors and also an employee, becoming a non-employee director due to termination of employment will not entitle the person to an Initial Option.

Annual Options. Each non-employee director automatically will receive, at the same time we make our annual equity awards to our executive officers, an annual award of a nonstatutory stock option (an Annual Option) to purchase shares of our common stock. Before the amendment of the policy in February 2024, each Annual Option covered a fixed number of 15,500 shares. From and after February 2024, each Annual Option will cover a fixed number of 29,400 shares. Each Annual Option will vest as to 1/12th of the shares subject to the option for each month of service after the date of the first annual meeting of our stockholders following the date of grant, and will vest in full on the earlier of (i) the twelve-month anniversary of the date of the first annual meeting of our stockholders following the date of grant or (ii) the date of the second regularly scheduled annual meeting of our stockholders that next follows the date of grant of the Annual Option, subject to continued service to us through the applicable vesting date. The term of each option granted under the policy will be 10 years, subject to earlier termination as provided in our Amended and Restated 2018 Omnibus Incentive Plan (the 2018 Plan). Each option granted under the policy will have an exercise price per share equal to 100% of the fair market value per share on the date of grant.

Change in Control. In the event of a “change in control” (as defined in the 2018 Plan), each non-employee director will fully vest in his or her outstanding company equity awards provided that the non-employee director continues to be a non-employee director through the date of such change in control.

Strohl Consulting Agreement

William Strohl, Ph.D. is party to the Strohl Consulting Agreement (as defined below) pursuant to which Dr. Strohl provides consulting services to support our antibody engineering and research strategy and execution. For additional information regarding the consulting agreement with Dr. Strohl, see the section titled “Certain Relationships, Related Party and Other Transactions—Strohl Consulting Agreement.”

2024 Compensation

Directors who are also our employees receive no additional compensation for their service as directors. Mr. Schwarzer and Dr. Harler were our only employee directors during 2024. See the section titled “Executive Compensation” for additional information about Mr. Schwarzer’s and Dr. Harler’s compensation.

The following table presents the total compensation each of our non-employee directors received during the year ended December 31, 2024. Other than as set forth in the table, we did not pay any compensation or grant any equity awards or other incentive awards to any of our non-employee directors in 2024.